1. Field of the Invention
The present invention relates to a coating composition and more particularly, a superior anticorrosive coating composition for metals containing an epoxy resin.
2. Description of the Prior Art
A coating composition containing epoxy resin is known as an anticorrosive coating composition for metal. However, in order to show and keep good anticorrosive properties, it is necessary to remove the rust and to make sufficient treatment of the metal surface, before the application of the coating, up to the grade of St(or Sa) 2.5 of Swedish Standard SIS 05 59 00. If the metal surface is treated insufficiently, the coating shows less adherence and poorer anticorrosive properties.
In the Japanese patent gazette 49-4811, an epoxy resin composition containing a major part of common epoxy resin and a minor part of a modified epoxy resin modified by mononucleic phenolic carboxylic acid or its lower alkyl ester is disclosed. This epoxy resin composition can be used as an anticorrosive coating. However, this coating cannot be applied on a rusty surface.
It was desired to obtain a good coating composition showing good adherence and good anticorrosive properties when it was coated on a poorly treated metal surface or even on a rusty surface such as the grade of Sa 1 to Sa 1.5 of Swedish Standard SIS 05 59 00.